Sweet potato & ginger pie

Serves 10 1kg sweet potatoes 250g plain flour, plus extra for dusting 125g chilled unsalted butter, cubed, plus extra for greasing 3 eggs, plus 1 yolk 80ml cold water 150ml milk 1 tbsp freshly grated ginger 200g light brown sugar 330ml double cream 1 tsp ground cinnamon, plus extra for dusting juice of 1 lemon 1 tsp honey 50g icing sugar sea salt airtight wrap 23cm fluted, loose-bottomed, deep tart tin 2 large baking trays

Preheat the oven to 190°C/170°C fan/gas mark 5 and place the sweet potatoes on a baking tray. Bake for 40-45 mins until very soft. Allow to cool completely, then peel the sweet potatoes and mash in a bowl, using a fork. Set aside 2 tbsp of the mash.

In the meantime, to make the pastry, place the plain flour in a large mixing bowl and add the butter and a pinch of sea salt. Rub the butter into the flour, using the fingers and thumbs, until the mixture resembles breadcrumbs. In a jug, whisk together the egg yolk with the cold water, then mix into the flour and butter mixture slowly. Not all the liquid may need to be added if the mixture comes together into a dough sooner.

Knead the mixture with one hand for 1-2 mins until it is smooth. Wrap the pastry in an airtight wrap and leave to chill for 1 hr.

Grease the tart tin with butter. On a surface lightly dusted with flour, roll out the pastry to fit the tart tin, then cover the inside of the tin with the pastry, cutting to fit at the top. Pierce the bottom of the pie several times, then leave to chill for 30 mins.

Preheat the oven to 200°C/180°C fan/gas mark 6 and place the tart tin on a large baking tray. Bake for 10 mins until firm. Remove from the oven and turn the oven to 180°C/160°C fan/gas mark 4. In a large mixing bowl, whisk together the mashed sweet potatoes, the eggs, milk, ginger, sugar, 100ml of the double cream and the ground cinnamon. Stir in a pinch of the salt. Pour the mixture into the pastry case and bake for 1 hr until the filling is set and firm when gently shaken from side to side. Allow to cool completely.

In a food processor, blend together the reserved 2 tbsp of sweet potato mash with the lemon juice and honey until a fine puree. In a large mixing bowl, whisk the remaining double cream and the icing sugar for 1-2 mins until thick. Top the pie with the cream, then mix the sweet potato puree into the cream to create a swirl effect. Dust the pie with cinnamon, and serve.